NPEF Report on Military Receivers Calls for FCC Recision
June 20, 2011The National PNT Engineering Forum (NPEF) LightSquared Working Group has published a report of its tests of classified and commercial GPS receivers under LightSquared terrestrial transmission conditions. "At the conclusion of this NPEF effort significant concerns remain that operation of an ATC integrated service as originally envisioned by the FCC cannot successfully coexist with GPS."
The report calls for rescinding the FCC conditional waiver for LightSquared terrestrial transmitions, conducting more thorough studies on the potential impacts, including those from LightSquared handsets, and revisiting and readdressing the 2003-2010 authorizations that originally opened the window for this development. This NPEF group tested a variety of military receivers under classified categorization at White Sands Missile Range and Holloman Air Force Base, both in New Mexico; these are also known as "government receivers."
"Recommendation 1: Move to rescind the FCC conditional waiver (FCC Order DA 11-133) of January 26, 2011 authorizing terrestrial only ATC operation in the Mobile Satellite Service (MSS) 1525 - 1559 MHz Band.
Test results of the LightSquared Phase 0, Phase 1, and Phase 2 deployments of ATC transmitters utilizing the MSS band (1550.2 – 1555.2 MHz for Phase 0, 1526.3 – 1531.3/1550.2-1555.2 MHz for Phase 1, and 1526-1536/1545.2 – 1555.2 MHz for Phase 2) have demonstrated there are significant detrimental impacts to all GPS applications assessed as part of this NPEF effort. These impacts encompassed both US Government and commercial GPS applications. [. . . . ]
Recommendation 2: The U.S. Government should conduct more thorough studies on the operational, economic and safety impacts of operating the LightSquared Network, to include additional ATC signal configurations not currently in LightSquared planned spectrum phases, effects on timing receivers, as well as transmissions from LightSquared handsets.
Initial test results demonstrated that some applications (e.g. aviation) were able to operate with little to no degradation when only a 5 or 10 MHz channel (1526.3 – 1531.3 MHz or 1526 – 1536 MHz) in the lower portion of the MSS spectrum was utilized for the LightSquared broadcast. However, for other applications, GPS loss of function still occurs at unacceptable distances to LightSquared towers. Use of only the lower portion of the L-band MSS spectrum is not one of the planned Phases for the LightSquared Network evolution so only limited testing has been conducted under this scenario. [. . . . ]
Recommendation 3: Based on testing of representative ATC equipment which became available for the first time during this NPEF evaluation, we strongly recommend the FCC revisit and readdress the effects of the 2003-2010 ATC authorizations within the MSS L-Band spectrum on GPS applications.
At the conclusion of this NPEF effort significant concerns remain that operation of an ATC integrated service as originally envisioned by the FCC cannot successfully coexist with GPS. [ . . . . ]"
For a copy of the full report, click here.
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